1. Field of the Invention
The present invention relates to a display apparatus and a method of controlling the same.
2. Description of the Related Art
As liquid crystal display apparatuses, liquid crystal projectors have conventionally been known, which supply light from a light source to a liquid crystal panel and project the light that has passed through the liquid crystal panel to a projection plane, thereby displaying an image. These projectors generally control the voltage to be applied to each pixel of the liquid crystal panel for forming an image by matrix driving so as to change the alignment direction of the liquid crystal and adjust the light transmittance.
The physical size of a pixel will be smaller along with an increase in the number of pixels of a liquid crystal panel in the future. Then, for example, when displaying an image whose luminance largely changes between adjacent pixels, that is, if the voltages applied to the adjacent pixels have a large difference, the liquid crystal alignment direction is distorted due to the influence of the voltages of the horizontal pixels. This distortion eventually affects the transmittance of the liquid crystal and lowers the quality of a displayed image. For example, if a high-luminance pixel and a low-luminance pixel are adjacent to each other, display unevenness occurs so that one of the pixels partially darkens or brightens.
To solve this problem, Japanese patent literature 1 (Japanese Patent Laid-Open No. 2009-104053) discloses a technique of calculating the tone difference between two pixels adjacent to each other out of a plurality of pixels and correcting an image signal so as to make the calculated difference small.
In patent literature 1, however, the tones of the adjacent pixels in the image signal are compared and corrected. Since the balance in the entire image or the like is not taken into consideration, the image quality may lower anew in the corrected image signal.